Antti Markkola

3D spin-lock imaging of human gliomas

We investigated whether the simultaneous use of paramagnetic contrast medium and 3D on-resonance spin lock (SL) imaging could improve the contrast of enhancing brain tumors at 0.1 T. A phantom containing serial concentrations of gadopentetate dimeglumine (Gd-DTPA) in cross-linked bovine serum albumin (BSA) was imaged. Eleven patients with histologically verified glioma were also studied. T1-weighted 3D gradient echo images with and without SL pulse were acquired before and after a Gd-DTPA injection. SL effect, contrast, and contrast-to-noise ratio (CNR) were calculated for each patient. In the glioma patients, the SL effect was significantly smaller in the tumor than in the white and gray matter both before (p = 0.001, p = 0.025, respectively), and after contrast medium injection (p < 0.001, p < 0.001, respectively). On post-contrast images, SL imaging significantly improved tumor contrast (p = 0.001) whereas tumor CNR decreased slightly (p = 0.024). The combined use of SL imaging and paramagnetic Gd-DTPA contrast agent offers a modality for improving tumor contrast in magnetic resonance imaging (MRI) of enhancing brain tumors. 3D gradient echo SL imaging has also shown potential to increase tissue characterization properties of MR imaging of human gliomas.

APCAP - activated protein C in acute pancreatitis: a double-blind randomized human pilot trial

IntroductionPrevious human studies have shown low activity of protein C (APC) in severe acute pancreatitis (SAP). This, together with the findings in animal models, suggests that activated protein C (APC) may protect against pancreatic injury and ameliorate the disease. We, therefore, evaluated its effect on multiple organ dysfunction (MOD) measured by the SOFA (Sequential Organ Failure Assessment) and on organ-failure-free days, and the safety of APC in SAP.MethodsA prospective double blind randomized pilot study was use. The study occurred in one university hospital tertiary intensive care unit (ICU) with eight beds. The patients were chosen according to the following inclusion criteria: 1) Those admitted to the hospital < 96 h from the onset of pain, 2) Those who had a three-fold increase in serum amylase over normal upper range or/and in whom computed tomography (CT) verification of SAP was noted, 3) Those who had one or more organ dysfunction (OD), and 4) Those in whom less than 48 hours had passed since their first OD. Of a total of 215 adult patients with SAP screened between June 2003 and August 2007, 158 fulfilled the study inclusion criteria. After exclusions 32 patients were randomized to the study. The intervention consisted of APC (N = 16) administered intravenously for 96 hours with a dose of 24 μg/kg/hour or placebo (N = 16) with a similar infusion rate. The sample size for the study was calculated according to the primary end-point: the change in SOFA during study drug infusion (Days 0 and 5). Comparisons between the study groups were performed using patient-related changes and calculation of difference in means (DIM, 95% CIs) and regarding categorical variables with Fishers exact test. For all comparisons P < 0.05 was considered significant.ResultsNo serious bleeding was detected clinically or by CT scans in either group. No significant difference in SOFA score change between the APC and placebo groups was found (difference in means (DIM) +2.3, 95% CI -0.7 to +5.3). Treatment with APC was associated with an increase in serum levels of both total and conjugated bilirubin. No differences in ventilator-free days, in renal replacement therapy-free days, in vasopressor-free days, or in days alive outside the hospital were detected.ConclusionsNo serious bleeding or differences in the evolution of MOD were detected between APC and the placebo. Instead we found an increase in serum bilirubin in the APC group compared to the placebo group in patients with SAP.Trial registrationClinicalTrials.gov NCT01017107.

Gd-dtpa as an alternative contrast agent in conventional and interventional radiology

Purpose: Patients with contra-indications to iodine-based contrast media present problems in radiological examination. In this study, we evaluated Gd-DTPA as an alternative contrast agent in conventional and interventional radiology Material and Methods: The undiluted contrast agent Gd-DTPA meglumine (469 mg/ml, Magnevist) was used in 10 examinations in 8 patients. A dosage of 20-45 ml was used in 5 conventional studies: endoscopic retrograde cholangiography, cystography, urethrocystography, and 2 retrograde pyelographies. A dosage of 10-120 ml was used in 5 interventions: 1 percutaneous nephrostomy, and 4 biliary tract drainages Results: The image quality was adequate in all studies. No adverse pharmacological reactions occurred; however, there was renal extravasation of Gd-DTPA which did cause temporary pain in 1 patient at bilateral retrograde pyelography Conclusion: Gd-DTPA may be used as an alternative contrast medium in selected conventional and interventional roentgenological studies when iodine is contra-indicated

Safety of granulocyte colony-stimulating factor (filgrastim) in intubated patients in the intensive care unit: interim analysis of a prospective, placebo-controlled, double-blind study.

ObjectiveTo investigate the safety of the granulocyte colony-stimulating factor filgrastim in the prevention of nosocomial infections in intubated patients in the intensive care unit (ICU), with special emphasis on the possible deleterious effect on acute respiratory distress syndrome (ARDS) and the development of multiple organ dysfunction (MOD). DesignPredetermined, interim analysis of a prospective, randomized, placebo-controlled, double-blind trial. SettingUniversity hospital medical-surgical ICU. PatientsA total of 59 consecutive ICU patients, aged >18 yrs, admitted to the ICU no more than 12 hrs before the study, intubated because of ventilatory insufficiency no more than 48 hrs before the study, expected to stay in the ICU for >48 hrs, and had informed consent from the next relative. InterventionsPatients were randomized to receive either placebo or 300 &mgr;g of filgrastim subcutaneously once daily for 7 days. Measurements and Main ResultsNo significant differences were found in the number of patients developing ARDS (2 of 20 in the placebo group vs. 0 of 22 in the filgrastim group), disseminated intravascular coagulation (3 of 27 vs. 3 of 29), acute renal failure (1 of 27 vs. 1 of 23), or change in MOD. Data analysis showed nosocomial infections in 11 of 29 patients in the placebo group and in 7 of 30 patients in the filgrastim group (p = .266). The median (range) length of ICU stay was 8 (1–34) days in the placebo group and 6 days (1–28) in the filgrastim group. The day 28 mortality rate was 17% (5 of 29) in the placebo group and 13% (4 of 30) in the filgrastim group. No drug-related adverse events occurred. ConclusionFilgrastim is safe in intubated ICU patients, with no excess risk for development of ARDS or MOD.

Imaging requirements for medical applications of additive manufacturing

Additive manufacturing (AM), formerly known as rapid prototyping, is steadily shifting its focus from industrial prototyping to medical applications as AM processes, bioadaptive materials, and medical imaging technologies develop, and the benefits of the techniques gain wider knowledge among clinicians. This article gives an overview of the main requirements for medical imaging affected by needs of AM, as well as provides a brief literature review from existing clinical cases concentrating especially on the kind of radiology they required. As an example application, a pair of CT images of the facial skull base was turned into 3D models in order to illustrate the significance of suitable imaging parameters. Additionally, the model was printed into a preoperative medical model with a popular AM device. Successful clinical cases of AM are recognized to rely heavily on efficient collaboration between various disciplines – notably operating surgeons, radiologists, and engineers. The single main requirement separating tangible model creation from traditional imaging objectives such as diagnostics and preoperative planning is the increased need for anatomical accuracy in all three spatial dimensions, but depending on the application, other specific requirements may be present as well. This article essentially intends to narrow the potential communication gap between radiologists and engineers who work with projects involving AM by showcasing the overlap between the two disciplines.

On- and off-resonance spin-lock MR imaging of normal human brain at 0.1 T: possibilities to modify image contrast

The aim of the present investigation was to determine spin lock (SL) relaxation parameters for the normal brain tissues and thus, to provide basis for optimizing the imaging contrast at 0.1 T. 68 healthy volunteers were included. On-resonance spin lock relaxation time (T1rho) and off-resonance spin lock relaxation parameters (T1rho(off), Me/Mo), MT parameters (T1sat, Ms/Mo), and T1, T2 were determined for the cortical gray matter, and for the frontal and parietal white matters. The T1rho for the frontal and parietal white matters ranged from 110 to 133 ms and from 122 to 155 ms with locking field strengths from 50 microT to 250 microT, respectively. Accordingly, the values for the gray matter ranged from 127 to 155 ms. With a locking field strength of 50 microT, T1rho(off) for the frontal and parietal white matters were from 114 to 217 ms and from 126 to 219 ms, and for the gray matter from 136 to 267 ms with the angle between the effective magnetic field (B(eff)) and the z-axis (theta) ranging from 60 degrees to 15 degrees, respectively. The T1rho of the white and gray matters increased significantly with increasing locking field amplitude (p < 0.001). The T1rho(off) decreased significantly with increasing theta (p < 0.001). T1rho and T1rho(off) with theta > or = 30 degrees were statistically significantly shorter in the frontal than in the parietal white matters (p < 0.05). The duration, amplitude and theta of the locking pulse provide additional parameters to optimize contrast in brain SL imaging.

Determination of T1ρ values for head and neck tissues at 0.1 T : A comparison to T1 and T2 relaxation times

In order to optimize head and neck magnetic resonance (MR) imaging with the spin-lock (SL) technique, the T1rho relaxation times for normal tissues were determined. Furthermore, T1rho was compared to T1 and T2 relaxation times. Ten healthy volunteers were studied with a 0.1 T clinical MR imager. T1rho values were determined by first measuring the tissue signal intensities with different locking pulse durations (TL), and then by fitting the signal intensity values to the equation with the least-squares method. The T1rho relaxation times were shortest for the muscle and tongue, intermediate for lymphatic and parotid gland tissue and longest for fat. T1rho demonstrated statistically significant differences (p < 0.05) between all tissues, except between muscle and tongue. T1rho values measured at locking field strength (B1L) of 35 microT were close to T2 values, the only exception being fat tissue, which showed T1rho values much longer than T2 values. Determination of tissue relaxation times may be utilized to optimize image contrast, and also to achieve better tissue discrimination potential, by choosing appropriate imaging parameters for the head and neck spin-lock sequences.

CT of the chest and abdomen in patients with newly diagnosed head and neck squamous cell carcinoma

The benefits of CT scanning of the chest and abdomen as a routine screening method for patients with newly diagnosed head and neck squamous cell carcinoma (HNSCC) remain unclear.

Cartilage invasion of laryngeal cancer detected by magnetic resonance imaging

Abstract Cartilage invasion of laryngeal cancer has a significant impact on the choice of treatment modality and on the outcome for the patients. Cartilage invasion was evaluated radiologically and histopathologically in 18 patients who underwent total laryngectomy. The histopathological examination showed intracartilaginous tumor spread in nine specimens, whereas in the other nine no cartilage invasion was found. Magnetic resonance imaging (MRI) detected the cartilage invasion in six patients and excluded it in six. There were three false negative and three false positive findings from the MRI examination. The relatively common false findings of MRI should be kept in mind in the choice of treatment.

MR Imaging Features of Acute Mastoiditis and Their Clinical Relevance

BACKGROUND AND PURPOSE: MR imaging is often used for detecting intracranial complications of acute mastoiditis, whereas the intratemporal appearance of mastoiditis has been overlooked. The aim of this study was to assess the imaging features caused by acute mastoiditis in MR imaging and their clinical relevance. MATERIALS AND METHODS: Medical records and MR imaging findings of 31 patients with acute mastoiditis (21 adults, 10 children) were analyzed retrospectively. The degree of opacification in the temporal bone, signal and enhancement characteristics, bone destruction, and the presence of complications were correlated with clinical history and outcome data, with pediatric and adult patients compared. RESULTS: Most patients had ≥50% of the tympanic cavity and 100% of the mastoid antrum and air cells opacified. Compared with CSF, they also showed intramastoid signal changes in T1 spin-echo, T2 TSE, CISS, and DWI sequences; and intramastoid, outer periosteal, and perimastoid dural enhancement. The most common complications in MR imaging were intratemporal abscess (23%), subperiosteal abscess (19%), and labyrinth involvement (16%). Children had a significantly higher prevalence of total opacification of the tympanic cavity (80% versus 19%) and mastoid air cells (90% versus 21%), intense intramastoid enhancement (90% versus 33%), outer cortical bone destruction (70% versus 10%), subperiosteal abscess (50% versus 5%), and perimastoid meningeal enhancement (80% versus 33%). CONCLUSIONS: Acute mastoiditis causes several intra- and extratemporal changes on MR imaging. Total opacification of the tympanic cavity and the mastoid, intense intramastoid enhancement, perimastoid dural enhancement, bone erosion, and extracranial complications are more frequent in children.